Storage and sub-atmospheric delivery of dopant compositions for carbon ion implantation

Abstract

A supply source for delivery of a CO-containing dopant gas composition is provided. The composition includes a controlled amount of a diluent gas mixture such as xenon and hydrogen, which are each provided at controlled volumetric ratios to ensure optimal carbon ion implantation performance. The composition can be packaged as a dopant gas kit consisting of a CO-containing supply source and a diluent mixture supply source. Alternatively, the composition can be pre-mixed and introduced from a single source that can be actuated in response to a sub-atmospheric condition achieved along the discharge flow path to allow a controlled flow of the dopant mixture from the interior volume of the device into an ion source apparatus.

1 . A dopant gas composition for use in an ion implantation process, comprising:
 an inert diluent gas mixture comprising xenon (Xe) and hydrogen (H2), wherein the Xe and the H2 are contained in an effective amount, said effective amount being in a volume ratio of Xe:H2 from about 0.02 to about 0.20; and   a carbon-based material contained in a volume ratio of (Xe+H 2 ):(carbon-based material) ranging from about 0.10 to about 0.30.   
     
     
         2 . The dopant gas composition of  claim 1 , wherein the dopant gas composition is located upstream of an ion source chamber. 
     
     
         3 . The dopant gas composition of  claim 1 , wherein the dopant gas composition is located in an ion source chamber. 
     
     
         4 . A method for dispensing a dopant gas composition for ion implantation comprising:
 introducing one or more carbon-containing dopant gases into an ion source chamber;   introducing a diluent gas composition into the ion source chamber in a volume ratio of Xe:H2 from about 0.02 to about 0.20;   ionizing the one or more carbon-containing dopant gas sources to produce carbon ions; and   implanting the carbon ions into a substrate.   
     
     
         5 . A method of preparing an inert diluent gas mixture suitable for use in ion implantation, comprising:
 filling a sub-atmospheric delivery and storage device with Xe and H2;   producing a pressurized mixture wherein the Xe and the H2 contained in a volume ratio of Xe:H2 from about 0.02 to about 0.20;   retaining a vacuum-actuated valve in a sealed configuration to maintain the mixture within the device at a predetermined storage pressure.   
     
     
         6 . The method of  claim 5 , further comprising the step of supplying said inert diluent gas mixture as part of a gas kit configured for use in ion implantation. 
     
     
         7 . A method of preparing a carbon source mixture, comprising:
 filling a sub-atmospheric delivery and storage device with CO;   filling the device with Xe and H2; and   producing a pressurized mixture wherein the Xe and the H2 are contained in a volume ratio of Xe:H2 from about 0.02 to about 0.20.   
     
     
         8 . The method of  claim 7 , further comprising filling the device with said CO in a volume ratio of (Xe+H 2 ):CO ranging from about 0.10 to about 0.30. 
     
     
         9 . The method of  claim 7 , further comprising:
 retaining a vacuum-actuated valve in a sealed configuration; and   maintaining the mixture within the device at a predetermined storage pressure.   
     
     
         10 . A diluent gas mixture suitable for use in a carbon-containing ion implantation process, said diluent gas mixture comprising xenon (Xe) and hydrogen (H2), wherein the Xe and the H2 are contained in an effective amount, said effective amount being in a volume ratio of Xe:H2 from about 0.02 to about 0.20, and further wherein said mixture is characterized by a substantial absence of a xenon-hydrogen compound. 
     
     
         11 . The diluent gas mixture of  claim 10 , wherein said Xe and said H2 are supplied as part of a gas kit. 
     
     
         12 . The diluent gas mixture of  claim 10 , further comprising a separate supply vessel comprising a carbon-containing material. 
     
     
         13 . The diluent gas mixture of  claim 12 , wherein said carbon-containing material comprises CO. 
     
     
         14 . The diluent gas mixture of  claim 13 , wherein said CO is characterized by a substantial absence of ionic mixtures, oxides and moisture. 
     
     
         15 . The diluent gas mixture of  claim 10 , wherein said diluent gas mixture is further characterized by the substantial absence of moisture, ionic mixtures, CO, CO2 and other oxides.